I would first look at the track clips and make sure you have not melted one into the hyfax material on the rails. Check the rails on both sides and make sure every one is free. In the spring season, with lack of snow coming into the tunnel, that can happen. The hyfax heats the metal of the track clips, and when the sled stops, the clips can melt into the hyfax.
It only takes one clip that is melted into the hyfax to keep the sled from moving.
If they are all free, then get the sled up on a stand and try to rotate the track by hand. You should be able to narrow down where the problem is.
2007 RMK 700, 2008 RMK 600, 1995 AC Prowler 2-up, 1980? AC Cheetah